1. Field of the Invention
Embodiments of the present disclosure relate to reinforcements for composite materials and, in particular, concerns electrophoretic deposition of carbon nanotubes on fiber substrates to form hybrid carbon nanotube fiber reinforcements.
2. Description of the Related Art
The use of high-performance, fiber-reinforced composites has expanded substantially in recent years, as improvements in these composites have allowed them to meet the final performance requirements of advanced aerospace systems. For example, extensive research and development in carbon fiber-reinforced composites has led to significant improvements in the properties of these composites, such as in-plane mechanical properties. Furthermore, composites formed using 2-D and 3-D woven fiber reinforcements can be formed into the final net shapes.
The out-of-plane properties of fiber-reinforced composites remain problematically low, however. Out-of-plane properties are dominated by the matrix surrounding the reinforcing fibers, which is relatively weak compared to the fibers. Additionally, fiber-reinforced composites generally possess matrix-rich regions within the interlaminar region between the fibers and these regions have proven difficult to reinforce with fiber reinforcements. As a result, cracks may easily initiate and propagate under load within these regions, leading to composite failure.
From the foregoing, then, there exists a continued need for improved reinforcements for composite materials.